The isolated hills to the north of Shiraz, separated from each other by ravines, are locally called tang. Of these, Allah Akbar Gorge is the most famous. It is located between Mount Chehel Maqam and Mount Baba Kuhi and is watered by the famous Rokni spring and Roknabad qanat. From the top of the steep slopes of the gorge, which serves as a natural entrance to Shiraz, there is a striking view of the city. Since early times, travelers looking at the settlement below have been moved to exclaim, Allah Akbar ("God is Great"), the expression used for showing the highest delight. From this practice, the gorge is said to have received its name.
In the account of his travel to Shiraz, Lord Curzon wrote, “I caught sight, in the opening of a mountain pass, of a great cluster of solemn cypresses, and, below, the shimmer of mingled smoke and mist that floated above the roofs of a large town, lying in a hollow of a considerable plain. This was Shiraz, which in the words of its own singer, Saadi, 'turns aside the heart of the traveler from his native land'; Shiraz, the home of poets, and rose-bowers, and nightingales, the haunt of jollity, and the Elysian fields of love, praised in a hundred odes as the fairest gem of Iran."
The Koran Gate is the most conspicuous monument of the Allah Akbar Gorge. The original building, reportedly resembling the Mausoleum of Cyrus at Pasargadae, is said to have been created by Azod al-Dowleh. At that time, a copy of the Koran was placed on top of the gate, in accord with a popular Muslim belief that all travelers should pass underneath the Koran before taking any journey. Most locals also came here at the beginning of every month to pass through the gate so as to remain under the Koran's blessing till the month's end.
During the Zand period, a newer structure was built at the site, and two volumes of an exquisite copy of the Koran, written in fine Tholth by Ibrahim Sultan, son of Shahrokh Timurid, were placed there. A water cistern was also built; it collected water from the Roknabad qanat and made it available to travelers. By the Qajar period, this building was badly damaged and needed repairs, which were carried out at the expense of Mohammad Zeki Khan Nuri. The edifice remained until 1937 when it was torn down to widen the street.
The modern building of the Koran Gate was constructed in 1949 by the local merchant Hossein Igar, who in accordance with his will was buried in the room in the east wing of the building. The Timurid Koran was replaced with a simpler copy and brought to the Pars Museum. There it was preserved until a couple of years ago when it was reported stolen, causing great consternation. The Koran Gate remained the main passageway to northern Shiraz until 1987 when due to heavy traffic the gorge was widened, and a modern highway was constructed to the east of the gate.